During a typical valve job, valve seats of the cylinder heads are resurfaced. Some cylinder heads have integral valve seats, while others have replaceable hardened steel valve seats. Replaceable valve seats can be removed and replaced. Integral seats are typically milled to allow the insert of a new seat. After resurfacing valve seats, the distance from the valve seat to the opposite side of the cylinder head may have decreased, which affects valve lash.
Valve lash or valve clearance is the gap between the rocker arms or bucket followers and the valve tip. In engines with rocker arms, a threaded rod or an eccentric at the end of each rocker arm adjusts the clearance to the top of the valve. In engines with overhead cams, bucket followers with calibrated shims, either above or below the buckets, are used to define the clearance. This clearance must be tightly controlled—too little and the valves may not seat properly, too much creates valve train noise and excess load on the valves and valve train components.
Often, after resurfacing valve seats and installing new valves, shims must be used to ensure proper height and clearance. As shims vary considerably in dimensions and configuration, and vary among corresponding followers, machinists must frequently order shims as needed. Maintaining an inventory of shims is impractical for many machinists. Ordering consumes time, which, means delayed job completion and delayed payment.
What is needed is a tool to precisely grind the tip of valves to provide proper clearance. The tool should be relatively inexpensive, easy to use and produce a tip with a planar top ground to a desired relative height.
The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.